This application claims a priority based on Japanese Patent Application No. 2000-12811 filed on Jan. 21, 2000, the entire contents of which are incorporated herein by reference for all purposes.
The present invention relates to a technology to control a movement of an object in a virtual field displayed on a display device according to manipulation contents of a manipulator, which are received via a controller having manipulation sticks such as joysticks.
In recent years, an entertainment apparatus such as a TV game machine has been spread, which is capable of performing a flight simulation, a drive simulation or the like by the use of a three dimensional graphic animation.
In this kind of entertainment apparatus, the manipulator (player) uses a controller such as an analog joystick or a game controller having the manipulation sticks and manipulation buttons, and controls an object that represents an airplane, an automobile or the like. Thus, the manipulator can move the object in a virtual three dimensional field. The entertainment apparatus generates a moving picture obtained by photographing the object, which moves in the three dimensional field, by the use of a virtual camera, and displays the moving picture on a display screen of a display device connected to the entertainment apparatus.
In this kind of entertainment apparatus, a posture and a moving direction of the object moving in the virtual three dimensional field have heretofore been controlled according to the manipulation contents applied to the manipulation sticks of the controller. For example, in a flight simulation, the manipulation sticks are made to possess the same function as that of a control stick, and a bank of an airplane, and rise and drop of a nose of the airplane, which is represented by the object, are determined by manipulation applied to the manipulation sticks. Moreover, in the drive simulation, the manipulation sticks are made to possess the same function as that of a steering wheel, and a tire direction of an automobile, which is represented by the object, is determined by manipulation applied to the manipulation sticks.
Incidentally, in the actual world, an extremely high control technique is required for a motion to allow an airplane to shift to a complete circular flight by the use of a control stick or a motion to allow an automobile to make a sharp turn by the use of a steering wheel. For this reason, if the manipulation sticks of the controller are merely allowed to possess the same function as that of the manipulation stick similarly to a conventional entertainment apparatus, an operation of a controlled object becomes extremely difficult, and an unskilled player might not be able to enjoy the flight simulation, the drive simulation or the like satisfactorily.
Accordingly, the objective of the present invention is to make it possible for even the unskilled player to enjoy the flight simulation, the drive simulation or the like satisfactorily.
To achieve the foregoing objective, in the present invention, in an entertainment apparatus which displays an object (object representing, for example, an airplane or an automobile) moving in a virtual field on a display device according to manipulation contents of a player, the manipulation contents being received via a controller having a manipulation stick, which is constituted so as to be pivotally tilted using a specified fulcrum relative to a specified axis passing through the specified fulcrum, a moving direction of the object is determined based on a signal in accordance with coordinate values on X-Y coordinate decided depending on a tilt direction and tilt angle of the manipulation stick relative to the specified axis of the manipulation stick, the signal being outputted from the controller, and when the coordinate value is within specified ranges, it is judged that the object is made to perform a specific motion, and the motion of the object in the virtual field is controlled.
For example, in the case where the entertainment apparatus is the one that displays on a display screen of a display device a moving picture obtained by photographing an object representing an airplane, which moves in the virtual three dimensional field according to the manipulation contents of the player received via the controller, by the use of a virtual camera, manipulation content reception means determines the moving direction of the object, (bank of the airplane and rise and drop of a nose of the airplane represented by the object) based on a signal according to coordinate values on X-Y coordinate, the signal being outputted from the controller, and when the coordinate values are within specified ranges, it is judged that the object is made to perform a specified motion (motion considered to be difficult for a player to operate in the actual world, for example, a sharp turn flight), and the moving direction of the object is determined so that the object can perform the specific motion.
With such constitution, it is possible to allow even an unskilled player to make the object perform a motion considered to be difficult to operate in the actual world with a relatively easy manipulation to the manipulation stick. Accordingly, even the unskilled player can enjoy the flight simulation, the drive simulation or the like satisfactorily, thus improving entertainingness.